GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2007 🢒 VUE - AWD 🢒 Engine 🢒 Engine Controls and Fuel - 3.5L (L66) 🢒 Backfire

Backfire

Checks

Action

DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.

Preliminary Check
    • Refer to Diagnostic System Check - Vehicle .
    • Refer to Symptoms - Engine Controls .

Ignition System Checks
    • Check for the proper ignition coil output voltage with a J 26792 Spark Tester or equivalent.
    • Inspect the spark plugs for correct operation and good ignition system performance. Refer to Spark Plug Inspection .
    • Inspect the ignition coil boots for damage.

Engine Mechanical Checks
    • Check for any of the following engine mechanical problems:
       - Any broken or weak valve springs
       - A low compression
       - Any sticking or leaking valves
       - An incorrect valve timing
       - An incorrect or worn camshaft
       - Refer to Symptoms - Engine Mechanical .
    • Check the intake and the exhaust system for casting flash or other restrictions.